```html
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    <title>Java垃圾回收机制深度解析</title>
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<body class="bg-gray-50">
    <!-- Hero Section -->
    <div class="relative h-96 bg-cover bg-center" style="background-image: url('https://images.unsplash.com/photo-1551288049-bebda4e38f71?ixlib=rb-1.2.1&auto=format&fit=crop&w=1350&q=80');">
        <div class="hero-overlay absolute inset-0 flex items-center justify-center">
            <div class="container mx-auto px-6 text-center text-white">
                <h1 class="text-4xl md:text-5xl font-bold mb-4 font-serif">Java垃圾回收机制</h1>
                <p class="text-xl md:text-2xl mb-8">深入理解JVM内存管理与性能优化</p>
                <div class="inline-block bg-white text-blue-600 px-6 py-3 rounded-full font-medium hover:bg-blue-100 transition duration-300">
                    <i class="fas fa-book-open mr-2"></i>探索更多
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    <!-- Main Content -->
    <div class="container mx-auto px-6 py-12 max-w-5xl">
        <!-- Introduction -->
        <div class="mb-16">
            <p class="text-lg text-gray-700 drop-cap">垃圾回收器并不会立即回收变量指向的对象。GC的工作是基于对象的可达性，而不是变量的生命周期。垃圾回收的触发是由JVM内部的算法和策略决定的，以确保内存的有效管理。</p>
        </div>

        <!-- Section 1 -->
        <div class="grid md:grid-cols-2 gap-8 mb-16">
            <div>
                <h2 class="text-2xl font-bold mb-4 text-blue-700 border-b-2 border-blue-200 pb-2 flex items-center">
                    <i class="fas fa-recycle mr-3"></i>垃圾回收的基本原理
                </h2>
                <div class="space-y-4">
                    <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                        <h3 class="text-xl font-semibold mb-2 text-gray-800">可达性分析</h3>
                        <p class="text-gray-700">垃圾回收器通过跟踪对象的引用链来确定哪些对象是可达的。只有那些不可达的对象（即没有任何引用指向它们的对象）才会被回收。</p>
                    </div>
                    <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                        <h3 class="text-xl font-semibold mb-2 text-gray-800">根对象</h3>
                        <p class="text-gray-700">可达性分析从一组称为"根对象"的对象开始，这些根对象包括栈上的引用、本地变量、静态字段等。</p>
                    </div>
                </div>
            </div>
            <div class="flex items-center justify-center">
                <div class="mermaid w-full">
                    graph LR
                    A[根对象] --> B[对象A]
                    A --> C[对象B]
                    B --> D[对象C]
                    C --> D
                    D --> E[对象D]
                    F[不可达对象]
                </div>
            </div>
        </div>

        <!-- Section 2 -->
        <div class="mb-16">
            <h2 class="text-2xl font-bold mb-6 text-blue-700 border-b-2 border-blue-200 pb-2 flex items-center">
                <i class="fas fa-clock mr-3"></i>GC不会立即回收变量
            </h2>
            <div class="grid md:grid-cols-2 gap-8">
                <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                    <h3 class="text-xl font-semibold mb-2 text-gray-800">变量生命周期</h3>
                    <p class="text-gray-700">当变量超出其作用域或生命周期结束时，它指向的对象不一定会被立即回收。垃圾回收的触发是基于堆内存的使用情况和GC策略，而不是单个变量的生命周期。</p>
                </div>
                <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                    <h3 class="text-xl font-semibold mb-2 text-gray-800">对象可达性</h3>
                    <p class="text-gray-700">即使变量不再可用，只要对象仍然可以通过其他引用（例如全局变量、静态字段或其他对象）访问，它就不会被回收。</p>
                </div>
            </div>
        </div>

        <!-- Section 3 -->
        <div class="mb-16">
            <h2 class="text-2xl font-bold mb-6 text-blue-700 border-b-2 border-blue-200 pb-2 flex items-center">
                <i class="fas fa-bell mr-3"></i>GC触发条件
            </h2>
            <div class="grid md:grid-cols-3 gap-6">
                <div class="card-hover bg-white p-6 rounded-lg shadow-md text-center">
                    <div class="text-4xl text-blue-600 mb-4">
                        <i class="fas fa-exclamation-triangle"></i>
                    </div>
                    <h3 class="text-xl font-semibold mb-2 text-gray-800">内存不足</h3>
                    <p class="text-gray-700">当JVM发现堆内存即将用尽时，GC会被触发。</p>
                </div>
                <div class="card-hover bg-white p-6 rounded-lg shadow-md text-center">
                    <div class="text-4xl text-blue-600 mb-4">
                        <i class="fas fa-clock"></i>
                    </div>
                    <h3 class="text-xl font-semibold mb-2 text-gray-800">定时触发</h3>
                    <p class="text-gray-700">一些垃圾回收器（如G1）可以根据时间间隔或其他策略定期进行垃圾回收。</p>
                </div>
                <div class="card-hover bg-white p-6 rounded-lg shadow-md text-center">
                    <div class="text-4xl text-blue-600 mb-4">
                        <i class="fas fa-hand-paper"></i>
                    </div>
                    <h3 class="text-xl font-semibold mb-2 text-gray-800">显式调用</h3>
                    <p class="text-gray-700">调用<code>System.gc()</code>可以请求JVM执行垃圾回收，但JVM不一定会立即执行。</p>
                </div>
            </div>
        </div>

        <!-- Section 4 -->
        <div class="mb-16">
            <h2 class="text-2xl font-bold mb-6 text-blue-700 border-b-2 border-blue-200 pb-2 flex items-center">
                <i class="fas fa-cogs mr-3"></i>GC的工作过程
            </h2>
            <div class="grid md:grid-cols-3 gap-6">
                <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                    <div class="flex items-center mb-3">
                        <span class="inline-block w-8 h-8 bg-blue-600 text-white rounded-full flex items-center justify-center mr-3">1</span>
                        <h3 class="text-xl font-semibold text-gray-800">标记阶段</h3>
                    </div>
                    <p class="text-gray-700">GC标记所有可达的对象。</p>
                </div>
                <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                    <div class="flex items-center mb-3">
                        <span class="inline-block w-8 h-8 bg-blue-600 text-white rounded-full flex items-center justify-center mr-3">2</span>
                        <h3 class="text-xl font-semibold text-gray-800">清除阶段</h3>
                    </div>
                    <p class="text-gray-700">GC清除所有未被标记的对象，释放内存。</p>
                </div>
                <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                    <div class="flex items-center mb-3">
                        <span class="inline-block w-8 h-8 bg-blue-600 text-white rounded-full flex items-center justify-center mr-3">3</span>
                        <h3 class="text-xl font-semibold text-gray-800">整理阶段</h3>
                    </div>
                    <p class="text-gray-700">对于某些垃圾回收算法，将存活对象移动到堆的一端，整理内存以减少碎片。</p>
                </div>
            </div>
        </div>

        <!-- Section 5 -->
        <div class="mb-16">
            <h2 class="text-2xl font-bold mb-6 text-blue-700 border-b-2 border-blue-200 pb-2 flex items-center">
                <i class="fas fa-exclamation-circle mr-3"></i>例外情况
            </h2>
            <div class="grid md:grid-cols-2 gap-8">
                <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                    <h3 class="text-xl font-semibold mb-2 text-gray-800">强引用</h3>
                    <p class="text-gray-700">如果对象仍然被强引用（即变量仍然引用该对象），即使垃圾回收器检测到该对象已经不再使用，它也不会被回收。</p>
                </div>
                <div class="card-hover bg-white p-6 rounded-lg shadow-md">
                    <h3 class="text-xl font-semibold mb-2 text-gray-800">弱引用和软引用</h3>
                    <p class="text-gray-700">使用<code>WeakReference</code>或<code>SoftReference</code>创建的对象在不同的条件下可能会被回收。例如，软引用对象通常在内存不足时被回收，而弱引用对象在下一次GC时就会被回收。</p>
                </div>
            </div>
        </div>

        <!-- Section 6 -->
        <div class="mb-16">
            <h2 class="text-2xl font-bold mb-6 text-blue-700 border-b-2 border-blue-200 pb-2 flex items-center">
                <i class="fas fa-code mr-3"></i>示例代码
            </h2>
            <div class="code-block">
                <span class="language">Java</span>
                <pre>
public class GCDemo {
    public static void main(String[] args) {
        GCDemo demo = new GCDemo();
        demo.createObject();
        
        // 触发垃圾回收
        System.gc();
        
        // 模拟长时间运行
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    
    public void createObject() {
        // 创建一个新的对象
        Object obj = new Object();
        // obj 在这个方法内是局部变量，方法结束后 obj 不再可用
    }
}</pre>
            </div>
            <div class="mt-4 text-gray-700">
                <p>在上面的示例中，<code>obj</code>是一个局部变量，方法结束后它不再可用。然而，这并不意味着<code>obj</code>立即被回收。GC将在适当的时候检测到<code>obj</code>相关的对象不再可达，并进行回收。</p>
            </div>
        </div>

        <!-- Summary -->
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            <h3 class="text-xl font-bold mb-4 text-blue-800">
                <i class="fas fa-lightbulb mr-2"></i>关键总结
            </h3>
            <ul class="list-disc pl-6 space-y-2 text-gray-700">
                <li>垃圾回收基于对象可达性而非变量生命周期</li>
                <li>GC触发时机由JVM内部策略决定</li>
                <li>不同引用类型影响对象回收时机</li>
                <li>显式调用<code>System.gc()</code>不保证立即执行</li>
                <li>理解GC机制有助于优化内存使用和性能</li>
            </ul>
        </div>
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```